In March 2025, ENSO-neutral conditions returned, with below-average sea surface temperatures (SSTs) weakening in the central and east-central equatorial Pacific Ocean [Fig. 1]. The westernmost Niño index values were near zero, while positive index values persisted in the easternmost Niño-3 and Niño-1+2 regions [Fig. 2]. Below-average subsurface temperatures weakened [Fig. 3], but negative anomalies continued in the central equatorial Pacific, extending to 250m depth [Fig. 4]. A shallow layer of above-average subsurface temperatures continued in the far eastern equatorial Pacific. Low-level wind anomalies remained easterly over the western and central Pacific, while upper-level wind anomalies were westerly over the central Pacific. Convection was suppressed around the Date Line and was enhanced near Indonesia [Fig. 5]. The traditional and equatorial Southern Oscillation indices were positive. Collectively, the coupled ocean-atmosphere system reflected ENSO-neutral conditions.

The IRI and North American multi-model ensemble indicate ENSO-neutral will continue through the summer [Fig. 6]. The forecast team also favors ENSO-neutral, with chances well over 50% through summer 2025. Because of reduced forecast accuracy in the spring, the uncertainty increases at longer time horizons, with a 43% chance of ENSO-neutral and a 38% chance of La Niña during November 2025 - January 2026 (chances of El Niño are under 20%). In summary, ENSO-neutral is favored during the Northern Hemisphere summer, with a greater than 50% chance through August-October 2025 [Fig. 7].